U.S. Pat. No. 5,844,213 (the 213 patent), titled Induction Heating Coil Assembly for Prevention of Circulating Currents in Induction Heating Lines for Continuous-Cast Products, discloses an induction heating coil assembly 24 that is used to inductively heat a single slab 26 as it passes through the coil assembly on conveyor rolls 27 and 29.
The disadvantage of the roller induction heating line in the 213 patent is that it is used to heat only one slab, or other workpiece, at a time. Therefore there is the need for an induction heating line that will heat multiple workpieces at the same time, and will allow each of the multiple workpieces to be inductively heated to varying degrees with use of one or more induction heating coil assemblies for all of the workpieces.